JP2009287791A - Vacuum heat insulating housing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum heat insulating housing having high performance and long-term reliability, and superior in stability in dimension. <P>SOLUTION: This vacuum heat insulating housing 1 has a vacuum double wall structure constituted by disposing a vacuum heat insulating material 4 formed by decompressing and sealing a fibrous core material, a gas adsorbing material 8 and a moisture adsorbing material 7 by a shell material composed of a gas poorly-permeating material, a powder core material 5, the gas adsorbing material 8 and the moisture adsorbing material 7 in a space 6 composed of an outer box 2 and an inner box 3 composed of the gas poorly-permeating material, and decompressing and sealing the space 6, respectively, the fibrous core material of the vacuum heat insulating material 4 has an orienting property, and the vacuum heat insulating material 4 is disposed so that the orienting direction of the fibrous core material is roughly perpendicular to the heat transferring direction of the vacuum heat insulating housing 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vacuum heat insulating box that can be used as a heat insulating material such as a refrigerator, a heat insulating cold jacket material, a vending machine, an electric water heater, a vehicle, etc.

  In recent years, energy saving is desired because of the importance of preventing global warming, which is a global environmental problem, and energy saving is also promoted for consumer devices.

  For example, in a heat-reserving liquid storage container incorporated in the circulation system of an automobile engine, combustion efficiency from the initial stage of engine operation can be secured by keeping warm and effective use of heated and cooled water. In addition, in a heat retaining container such as a jar pot, it contributes to energy saving by increasing the heat retaining performance. In cold storage applications such as refrigerators and vending machines, it will contribute to energy conservation by blocking heat entry and lowering the operating rate of the refrigeration system. From the above viewpoint, a high-performance heat insulating material is required.

  As general heat insulating materials, fiber materials such as glass wool and foams such as urethane foam are used. However, in order to improve the heat insulation performance of these heat insulating materials, it is necessary to increase the thickness of the heat insulating material, and there is a limit to the space that can be filled with the heat insulating material, so when space saving and effective use of the space are necessary It cannot be applied.

  Therefore, vacuum heat insulating materials have been proposed as high performance heat insulating materials.

  A vacuum heat insulating material is a heat insulating material in which a foamed resin, fiber material, inorganic powder, etc. is used as a core material and is put in a jacket material, and the heat conductivity of gas is remarkably lowered by keeping the inside of the heat insulating material in a vacuum. In order to maintain the heat insulation performance over a long period of time, it is necessary to keep the inside of the heat insulating material in a vacuum.

  In the case where heat conduction is performed through the presence of air, there is a mean free path of gas as a physical property that affects the heat insulation performance. The mean free path of a gas is the distance traveled until one of the molecules that make up the air collides with another molecule. If the void formed is larger than the mean free path, the molecules in the gap Since they collide with each other and heat conduction by gas occurs, the heat conductivity increases.

  The heat insulation principle of the vacuum heat insulating material is to eliminate heat conducting air as much as possible and reduce heat conduction by gas.

  Therefore, in order to maintain the performance of the vacuum insulator for a long period of time, the initial internal pressure needs to be lower. However, it is difficult to achieve a high vacuum at an industrial level, and the degree of vacuum that can be achieved practically is up to about 13 Pa.

  On the other hand, when the type of the core material is different, the air gap distance is changed, and even when the internal pressure is the same, the number of collisions between the gases is changed and the heat conduction is different. The smaller the gap distance, the smaller the number of collisions between the gases even at the same internal pressure, and the smaller the heat conduction by the gas. That is, as the core material having a smaller air gap distance is used, even if the internal pressure increases due to some influence, the increase in thermal conductivity due to the heat conduction of the gas is less and the heat insulation performance is less decreased.

  Since the heat insulation performance of the whole vacuum heat insulating material is also due to heat conduction by a solid such as a core material, the heat insulation performance is not necessarily superior as the gap distance is generally small, but can be properly used depending on the purpose.

  The principle and configuration of the vacuum heat insulating box is the same as the vacuum heat insulating material, but in general, the vacuum heat insulating material inserts the core material into the gas permeable outer covering material and seals it by reducing the inside. The outer jacket material is brought into close contact with the shape of the core member serving as a spacer by atmospheric compression. If the shape of the core material is complicated due to unevenness or bending, it becomes difficult to insert the core material into the outer cover material. It is difficult to follow and seal under reduced pressure.

  If molding does not follow, there is no point in giving shape to the core material, wrinkles on the outer cover material, floating without adhering to the core material, local stress is easily applied to the outer cover material, and the core The portion not in close contact with the material is easily damaged by a slight external force. Therefore, a general vacuum heat insulating material has a flat plate shape.

  However, it has followability to gentle unevenness and bending, and it can be bent or deformed after it is made into a flat plate shape. Arise.

  Therefore, the jacket material is molded into the required irregularities, bends and shapes in advance, the core material is inserted into a gas-permeable low-permeability box with strength that does not cause significant deformation by atmospheric compression, and sealed under reduced pressure Is distinguished from a vacuum heat insulating material to form a vacuum heat insulating box. If it is this method, the vacuum heat insulating material (vacuum heat insulation box) which has the unevenness | corrugation and bending more complex than a vacuum heat insulating material, and a box shape can be produced.

  In addition, it is called a vacuum heat insulation box, but it is not necessarily a box shape, the jacket material has a strength that does not greatly deform due to atmospheric compression, and has a hollow double wall structure. What is necessary is just a characteristic, and a magnitude | size and a shape are not ask | required. For example, a pipe shape, a shape having irregularities on a flat plate, a bottle shape, and a spherical shape are also included.

  By increasing the degree of vacuum inside the vacuum heat insulation box, high performance heat insulation performance can be obtained, but the gas existing inside the vacuum heat insulation box is roughly divided into the following three types. One is the gas that cannot be evacuated when the vacuum heat insulation box is manufactured, and the other is the gas generated from the core material and the jacket material after being vacuum-sealed (adsorbed to the core material and the jacket material). The remaining gas is a gas that enters from the outside through the jacket material, and the other one is a reaction gas generated by the reaction of unreacted components of the core material.

  As a factor that increases the internal pressure of the vacuum heat insulation box, in the long run, when the box is made of resin material, the vacuum heat insulation box is transmitted through the box part and the thermally welded resin layer. When a gas such as air or water vapor gradually enters the body from the outside, there is a problem that the degree of vacuum decreases and the heat insulation performance deteriorates. In the case of a metal casing, there is a risk that the heat insulation performance deteriorates due to poor welding or air components from pinholes.

  In addition, since the vacuum heat insulation box has a three-dimensional shape, it is generally difficult to completely fill the hollow double wall with a fibrous core material having low solid thermal conductivity and high heat insulation performance. Filling. In addition, when using a powdery core material whose heat insulation performance is slightly inferior to the fibrous core material, filling is possible, but it is not easy to fill the powder core material to the required density, and after filling, There is a problem that exhaust resistance is high, and it is necessary for a long time to evacuate, and sufficient decompression cannot be performed.

  As a technique for maintaining the vacuum degree of the vacuum heat insulating box, for example, there is Patent Document 1. In patent document 1, in a vacuum heat insulation box formed by filling a foam heat insulating material between an outer box and an inner box of a refrigerator or the like, an open cell rigid polyurethane foam is used for the foam heat insulating material, and a heat insulating wall is used for the outer box. A vacuum indicator and an open / close valve communicating with the inside are provided, and vacuum degassing is performed via the open / close valve.

  In the above configuration, the degree of vacuum inside can be monitored by a vacuum indicator that communicates with the inside of the heat insulation wall, so even if the degree of vacuum deteriorates due to gas that has entered from the outside or gas that has remained inside, the vacuum deaeration is performed via the open / close valve. By doing so, the initial heat insulation performance can be recovered.

Moreover, there exists patent document 2 as a method of enclosing powder between the double walls of a hollow double wall box, for example. In Patent Document 2, fine particles are forcibly introduced and filled together with air. At the same time, the inside of the container is depressurized from an inlet different from the sealing inlet so that the container is not deformed by the press-fitted air and is easily pressed. In addition, the pressure reducing port is made of metal mesh or non-woven fabric so that the powder does not leak. The sealing pressure is ^{2 to} 8 kg / cm ² G. In Patent Document 2, the vacuum heat insulation box is not formed, but as a powder enclosing method, a vacuum heat insulating box can also be applied.
JP-A-7-148752 Japanese Patent Laid-Open No. 2-269681

  However, in the conventional configuration described in Patent Document 1, in the vacuum heat insulating box, the gas entering from the outside and the gas generated from the inside are reduced again through the valve, but the inside of the box is reduced from the opening / closing valve. For this purpose, the exhaust resistance is large and it takes a very long time to reduce the pressure.

  Further, in Patent Document 1, open-celled rigid polyurethane foam is used as a core material. However, in open-celled rigid polyurethane foam, a large amount of gas is generated from the core material itself as the core material, and there is an air gap distance as the powder. Because of its large size, it is relatively inferior in heat insulation performance compared to a fibrous core, etc., and furthermore, if it is a powder such as silica powder having a finer particle size with a small gap distance, The exhaust resistance is further increased, and the pressure cannot be easily reduced, and a considerable time is required for the pressure reduction process. Furthermore, in order to obtain long-term reliability, it is difficult for ordinary households to reduce the pressure by a vacuum pump every time the internal pressure increases and the heat insulation performance deteriorates, and the cost also increases.

  Further, in the above-described conventional configuration described in Patent Document 2, a fine powder having a small air gap distance and a small mean free path and a relatively excellent heat insulation performance has a large exhaust resistance even when pressed together with air, so that the exhaust resistance is large. The air does not escape easily, and it takes a long time to fill with a density sufficient to withstand atmospheric compression by decompression, and the container may be deformed. Further, even if the remaining air is deaerated, there is a problem that exhaust resistance is large and time is required. If the amount enclosed is small or the vacuum heat insulation box is small, the time taken to enclose the powder core material will be reduced, which may not be a big influence, but it is a large vacuum heat insulation box like a refrigerator. In the body, there is a problem that the production process takes a very long time.

  An object of the present invention is to solve the above-mentioned conventional problems, and to provide a vacuum heat insulating box having high performance and long-term reliability, further improving productivity, and excellent in dimensional stability.

  In order to achieve the above object, the vacuum heat insulation box of the present invention is a fiber with a jacket material made of a gas-impermeable material in a space constituted by an outer box and an inner box each made of a gas-impermeable material. A vacuum core formed by vacuum-sealing the core material and a powder core material, and having a vacuum double wall structure in which the space is sealed under reduced pressure, and a fiber core as a core material of the vacuum heat insulation box It is the structure which used the powder core material in the space other than the vacuum heat insulating material which used the material, and the vacuum heat insulating material.

  The reason why air or water vapor enters the space between the inner box and the outer box of the vacuum heat insulation box of the present invention is because there is a pressure difference due to atmospheric pressure between the outside air and the space. Is made of a resin material, it passes through the box part and the heat-welded resin layer, and in the case of a metallic casing, the air component penetrates very slowly due to poor welding or pinholes.

  However, there is a powder core material in the space part of the vacuum heat insulation box, and the powder core material has a small air gap distance, and the deterioration of the heat insulation performance is small with respect to the increase in internal pressure. Has almost no effect and has long-term reliability.

  And the vacuum heat insulating material using the fibrous core material installed in the space is welded from the heat-welded layer if it is sealed with a laminate film, from the resin layer if it is welded with resin, and if it is welding of a metal material Air, water vapor, etc. enter the vacuum heat insulating material through defects or pinholes.

  However, since the pressure difference between the space and the vacuum heat insulating material is very small, air and water vapor hardly penetrate. Vacuum insulation material using a fibrous core material has low thermal conductivity due to solids and high performance, but since the air gap distance is large, the rate of heat insulation performance decreases with increasing internal pressure, so long-term reliability Is inferior to a vacuum heat insulating material using a powder core material, but can maintain high performance for a long period of time as long as air components hardly penetrate.

  Therefore, the combined vacuum insulation box can be provided as a vacuum insulation box having high performance and high reliability.

  Moreover, since the vacuum heat insulating material using the fibrous core material is inserted as the core material in the space of the vacuum heat insulating box body, the amount of the powder core material can be significantly reduced as compared to the entire space. This makes it possible to shorten the time required for encapsulating the powder core and reducing the pressure, thereby improving productivity.

  In addition, by using vacuum heat insulating material that has been compressed in the air in advance as the core material, even if the inside of the vacuum heat insulating box is depressurized, the vacuum heat insulating material is hardly deformed, so that deformation of the box due to atmospheric compression is suppressed. The vacuum heat insulation box body excellent in dimensional stability can be provided.

  High-performance vacuum insulation using a fibrous core material that has a large decrease in heat insulation performance against an increase in internal pressure, but the heat insulation performance is inferior to that of the fiber core material, but the air gap distance is small, and the internal pressure increase By using it as a core material of a vacuum heat insulation box together with a powder core material that has a small decrease in heat insulation performance, it has a configuration that takes advantage of both the fibrous core material and the powder core material, and has high performance, high reliability, and high dimensional stability. Therefore, it is possible to provide a vacuum heat insulating box body having improved properties and productivity.

  The invention of the vacuum heat insulation box according to claim 1 of the present invention is that a fiber made of a gas permeable material covering material in a space constituted by an outer box and an inner box each made of a gas permeable material. It is characterized by having a vacuum double-wall structure in which a vacuum heat insulating material and a powder core material obtained by sealing a core material under reduced pressure are disposed and the space is sealed under reduced pressure.

  The reason why air or water vapor enters the space between the inner box and the outer box of the vacuum heat insulation box of the present invention is because there is a pressure difference due to atmospheric pressure between the outside air and the space. Is made of a resin material, it passes through the box part and the heat-welded resin layer, and in the case of a metallic casing, the air component penetrates very slowly due to poor welding or pinholes.

  However, there is a powder core material in the space part of the vacuum heat insulation box, and the powder core material has a small air gap distance, and the deterioration of the heat insulation performance is small with respect to the increase in internal pressure. Has almost no effect and has long-term reliability.

  And the vacuum heat insulating material using the fibrous core material installed in the space is welded from the heat-welded layer if it is sealed with a laminate film, from the resin layer if it is welded with resin, and if it is welding of a metal material Air, water vapor, etc. enter the vacuum heat insulating material through defects or pinholes.

  However, since the pressure difference between the space and the vacuum heat insulating material is very small, air and water vapor hardly penetrate. Vacuum insulation material using a fibrous core material has low thermal conductivity due to solids and high performance, but since the air gap distance is large, the rate of heat insulation performance decreases with increasing internal pressure, so long-term reliability Is inferior to a vacuum heat insulating material using a powder core material, but can maintain high performance for a long period of time as long as air components hardly penetrate.

  Therefore, the combined vacuum insulation box can be provided as a vacuum insulation box having high performance and high reliability.

  Moreover, since the vacuum heat insulating material using the fibrous core material is inserted as the core material in the space of the vacuum heat insulating box body, the amount of the powder core material can be significantly reduced as compared to the entire space. This makes it possible to shorten the time required for encapsulating the powder core and reducing the pressure, thereby improving productivity.

  In addition, by using vacuum heat insulating material that has been compressed in the air in advance as the core material, even if the inside of the vacuum heat insulating box is depressurized, the vacuum heat insulating material is hardly deformed, so that deformation of the box due to atmospheric compression is suppressed. The vacuum heat insulation box body excellent in dimensional stability can be provided.

Further, the gas permeable material preferably has a gas permeability of 10 ⁴ [cm ³ · 20 μm / m ² · day · atm] or less, and more desirably 1 [cm ³ · 20 μm / m ² · day. · Atm] or less.

  Further, the gas-impermeable material of the vacuum heat insulation box includes metal materials such as stainless steel and iron, glass materials, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon, polyvinyl alcohol, crystals A gas-impermeable resin such as crystalline polyethylene terephthalate and crystalline syndiotactic polystyrene is preferred.

Further, by forming a film made of metal, SiO ₂ , Al ₂ O ₃ , and diamond-like carbon on the resin material, it is possible to impart further gas permeability and improve reliability.

  In addition, the resin material can be improved in reliability by insert molding a metal foil laminate film such as an AL foil laminate film or an AL vapor deposition laminate film.

  Furthermore, it is preferable to use a laminate film obtained by laminating a metal foil such as aluminum on a resin film as the gas permeable material of the vacuum heat insulating material. Metal foil has very high gas permeability and high reliability. Moreover, the barrier property which was excellent also in the vapor deposition layer instead of foil is produced. Moreover, it has a high gas permeability even when an inorganic material such as silica, alumina or diamond-like carbon is deposited instead of metal.

  Also, as with the gas-impermeable material of vacuum insulation box, metal materials such as stainless steel and iron, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon, polyvinyl alcohol, crystalline polyethylene terephthalate Alternatively, a gas permeable resin such as crystalline syndiotactic polystyrene may be used.

Further, by forming a film made of metal, SiO ₂ , Al ₂ O ₃ , and diamond-like carbon on the resin material, it is possible to impart further gas permeability and improve reliability.

  In addition, when a laminate film is used as a gas-impermeable material for vacuum insulation, if polyethylene is used for the heat-welded layer, polyethylene can be welded at a relatively low temperature, making it easier to weld by additional heating and lower cost. A vacuum insulation box can be provided.

  In addition, when the outermost layer of the laminate film has a protective layer, by providing a material for surface protection in the outermost layer, more reliable scratch resistance and piercing resistance can be exhibited, and pinholes and the like can be exhibited. The vacuum heat insulating material which has the effect | action which suppresses generation | occurrence | production and has long-term reliability can be provided. Among them, polyethylene terephthalate is an inexpensive material, and the vacuum heat insulating box of the present invention can be provided at a lower cost.

  The fibrous core material is not limited, but glass fiber, glass fiber, alumina fiber, silica alumina fiber, silica fiber, rock wool, silicon carbide fiber, etc. are preferable. Most desirable for forming insulation.

  The glass fiber is preferably in the range of 1 μm to 20 μm, more preferably 2 μm to 10 μm with rigidity as a core material, and more preferable in terms of productivity and thermal conductivity.

  Further, although the powder core material is not limited, the inorganic powder material is preferable because it originally retains the powder and generates less gas (outgas) from the powder during decompression.

  The invention of the vacuum heat insulation box according to claim 2 is the invention according to claim 1, wherein the outer cover material has a heat-sealing layer on the inner surface, and the heat of the outer cover material facing the outer cover material. The welding layers are heat-welded to the fibrous core material along the fibrous core material.

  Since the heat-welding layers of the facing jacket materials facing each other are thermally welded to the fibrous core material along the fibrous core material, the sealing performance is improved, and the fibrous core is between the jacket materials. It is possible to cut the portion without the material (fin portion) up to the fibrous core material, the area occupied by the vacuum heat insulating material can be improved, and the performance of the vacuum heat insulating box can be improved. In addition, the powder core can be easily filled by reducing the fin portion.

  Invention of the vacuum heat insulation box of Claim 3 WHEREIN: The invention of Claim 1 or 2 WHEREIN: The said fibrous core material of the said vacuum heat insulation has orientation, The heat transfer of the said vacuum heat insulation box The vacuum heat insulating material is arranged such that the orientation direction of the fibrous core material is substantially perpendicular to the direction.

  The fibrous core material is oriented in a direction perpendicular to the pressurizing direction when the fiber oriented in a random direction is pressed in one direction. Usually, in order to adjust the density, a compact is formed by applying pressure while adding a binder or heating.

  Since the fibrous core material undergoes solid heat conduction in the fiber direction, the solid heat conduction is easily transmitted in a direction parallel to the orientation direction by pressurization or the like. On the other hand, in the direction perpendicular to the orientation direction, the fibers are in point contact and the solid heat conduction is greatly reduced. Therefore, the heat insulation performance is higher in the direction perpendicular to the orientation direction. Therefore, effective heat insulation performance can be expressed by installing the vacuum heat insulating material in a direction substantially perpendicular to the orientation direction of the fibrous core material with respect to the heat transfer direction of the vacuum heat insulating box.

  Actually, making the orientation direction of the fibrous core material completely perpendicular to the heat transfer direction of the vacuum heat insulation box means that the heat transfer direction is not uniform and the fibrous core material is perfectly oriented. Since it is difficult because it is not, for example, the direction is substantially vertical, and the substantially vertical direction may be within an angle of 70 to 110 degrees with respect to the main heat transfer direction.

  The invention of the vacuum heat insulation box according to claim 4 is the invention according to any one of claims 1 to 3, wherein the powder core is dry silica having an average primary particle diameter of 100 nm or less. It is what.

  As the core material, the powder material in which the air gap distance is shorter is more excellent in pressure dependency, and therefore is superior to the fiber material in order to obtain long-term reliability. In addition, the solid thermal conductivity is low, and a silica-based material is excellent as a core material for a vacuum heat insulating material as a powder core material. Moreover, since the average primary particle diameter is 100 nm or less, the particle size is excellent in that the heat insulation performance with respect to the internal pressure is small, and such silica powder corresponds to dry silica produced by a dry method.

  Invention of the vacuum heat insulation box of Claim 5 WHEREIN: The invention of Claim 4 WHEREIN: The said powder core material is the said dry-type so that content to the said powder core material may be 0.5-40 wt%. A glass fiber material having an average fiber diameter of 10 μm or less is mixed with silica and subjected to pressure molding.

  Although dry silica has excellent performance as a core material for a vacuum heat insulating box, it is difficult to handle because of its low density, and man-hours are required for filling. Therefore, solidifying and encapsulating dry silica is excellent in the process.

  As a solidifying means, a general silica powder and a fiber material are mixed and stirred, and even if pressure-molded, it does not become a molded body. However, the dry silica having an average primary particle diameter of 100 nm or less according to the invention of claim 4 and A molded body can be formed by mixing and pressing with a fiber material.

  This may be due to the fact that powders with small particle diameters cause intermolecular forces to act and the powders adhere to each other, or because they are dry, the surface functional groups are few and the mutual repulsion is so small that the powders are likely to adhere to each other. Therefore, in order to produce a molded body by a molding method such as pressurization, it is necessary to use dry silica having an average primary particle diameter of 100 nm or less and a fiber material.

  Further, by making the glass fiber material have an average fiber diameter of 10 μm or less, the specific surface area is increased because the fiber diameter of the glass fiber is small, that is, the surface energy is increased, and the glass powder is easily combined with the powder. Since it is a combination with good affinity, it is considered that it is easy to adhere to each other or due to their interaction. Therefore, when producing a molded body by a molding method such as pressure, a glass having an average fiber diameter of 10 μm or less By using a fiber material, a stronger molded body can be produced.

  Further, by using dry silica having a very fine particle diameter and a glass fiber material having a small fiber diameter, a molded body having almost no dusting can be obtained. This is because, as described above, the intermolecular force between powders having a small particle diameter, adhesion between powders due to a small number of surface functional groups, good affinity between silica and glass fibers, large surface energy of thin fiber materials, etc. Can be considered.

  In addition, a strong molded body can be obtained by the above combination, and a molded body having flexibility can be obtained because it has elasticity.

  The reason for this is considered to be that, since fibers having an average fiber diameter of 10 μm or less are used, flexural elasticity is improved and flexibility can be obtained.

  The fiber addition amount is 0.5 to 40 wt% because if the addition amount is too small, the shape of the molded body cannot be maintained, and if it is too much, the heat insulation performance becomes dependent on the fiber and the heat insulation performance is deteriorated. .

  The invention of the vacuum heat insulation box according to claim 6 is characterized in that, in the invention according to claim 4 or 5, carbon black is mixed with 1 to 30 wt% of the dry silica.

  Thereby, heat insulation performance improves rather than the vacuum heat insulation box using the conventional dry-type silica powder or its molded object.

  As powders added to dry silica to improve heat insulation performance, for example, carbon black and titanium oxide are known to work as radiation prevention materials at high temperatures, but the addition of carbon black greatly improves heat insulation performance at low temperatures. It can be seen. Although this reason is not certain, it is considered that solid heat conduction is reduced by some action of silica powder and carbon black.

  The addition amount of the powdery carbon material is preferably 1 to 30 wt%. This is because if the addition amount is too small, there is no effect of improving the heat insulation performance, and if it is too large, the heat insulation performance becomes dependent on the powdered carbon material and the heat insulation performance deteriorates, or gas generation increases under reduced pressure. This is because the heat insulation performance deteriorates.

  The invention of a vacuum heat insulation box according to claim 7 is the gas adsorption for adsorbing the gas in the vacuum heat insulating material in the vacuum heat insulating material in the invention according to any one of claims 1 to 6. A material is provided.

  By providing a gas adsorbing material for adsorbing the gas in the vacuum heat insulating material in the vacuum heat insulating material, even if the box of the vacuum heat insulating box breaks for some reason, the vacuum heat insulating material has high performance. However, since the air penetration | invasion amount from a heat welding layer increases, reliability falls. However, by installing the gas adsorbing material in contact with the fibrous core material in the vacuum heat insulating material, it is possible to suppress an increase in internal pressure and maintain the reliability of the heat insulating performance.

  The gas adsorbent is not particularly limited, and the adsorption mechanism may be any of physical adsorption, chemical adsorption, occlusion, and sorption, but a substance that acts as a non-evaporable getter is good.

  Specifically, it is a physical adsorbent such as synthetic zeolite, activated carbon, activated alumina, silica gel, dosonite, hydrotalcite.

  As the chemical adsorbent, oxides of alkali metals and alkaline earth metals, hydroxides of alkali metals and alkaline earth metals, etc. can be used. In particular, lithium oxide, lithium hydroxide, calcium oxide, calcium hydroxide, Magnesium oxide, magnesium hydroxide, barium oxide, and barium hydroxide are effective.

  In addition, calcium sulfate, magnesium sulfate, sodium sulfate, sodium carbonate, potassium carbonate, calcium chloride, lithium carbonate, unsaturated fatty acid, iron compound and the like also act effectively.

  In addition, it is more effective to apply a getter material obtained by singly or alloying materials such as barium, magnesium, calcium, strontium, titanium, zirconium, vanadium, and lithium.

  Furthermore, in order to adsorb and remove at least nitrogen, oxygen, moisture, and carbon dioxide, the getter material can be applied in various mixtures.

  The invention of the vacuum heat insulation box according to claim 8 is the gas adsorption for adsorbing the gas in the vacuum heat insulating material in the vacuum heat insulating material in the invention according to any one of claims 1 to 7. A material is provided.

  By providing a gas adsorbing material for adsorbing the gas in the vacuum heat insulating material in the vacuum heat insulating material, the long-term reliability of the vacuum heat insulating box can be improved, and the vacuum heat insulating material can also maintain high performance. It becomes possible, and the reliability of the whole vacuum heat insulation box can be maintained.

  The invention of a vacuum heat insulation box according to claim 9 is the invention according to claim 7 or 8, characterized in that the gas adsorbent is ZSM-5 type zeolite subjected to copper ion exchange. is there.

  Copper ion exchanged ZSM-5 type zeolite has higher air adsorption per unit weight at room temperature than other zeolites and metal adsorbents, and can absorb a large amount of air in a small amount. Space can be made.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the same components as those of the above-described embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a vacuum heat insulation box according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of a vacuum heat insulating material installed in the space of the vacuum heat insulation box according to Embodiment 1 of the present invention. .

  In FIG. 1, a vacuum heat insulating box 1 includes an outer box 2, an inner box 3, a vacuum heat insulating material 4, and a powder core material 5 made of a gas poorly permeable material, each of an outer box 2 made of a gas hardly permeable material. And placing the vacuum heat insulating material 4, the powder core material 5, the moisture adsorbing material 7 and the gas adsorbing material 8 in the space 6 constituted by the inner box 3 and joining the outer box 2 and the inner box 3. The space 6 is hermetically sealed, and the air in the space 6 is exhausted from an exhaust port 9 that is installed in the outer box 2 and communicates the space 6 with the outside air. 1 is constructed. The inner box 3 has an opening 10 for taking in and out hot water and cold water.

  In FIG. 2, a vacuum heat insulating material 4 is an outer cover material 11 made of two gas-impermeable materials, covers a fibrous core material 12 formed by press-molding short glass fibers, and is in contact with the fibrous core material 12. Thus, the moisture adsorbing material 7 and the gas adsorbing material 8 are installed, the inside is decompressed, and the heat welding layers 13 of the outer covering material 11 facing each other are thermally welded to maintain a vacuum.

  Next, the manufacturing method of the vacuum heat insulation box 1 is demonstrated. The inner box 2 and the outer box 3 were formed by injection molding using crystalline syndiotactic polystyrene. The inner box 2 and the outer box 3 are injection-molded using molds that differ only in the upper surface, with the direction in which the opening 10 is located at the top.

  The opening 10 is formed on the upper surface of the inner box 2 by injection molding. After molding, each part is subjected to electroless plating to improve gas permeability. The electroless plating is Cu 3 μm / Ni 5 μm, and the welded portion is prevented from being plated with a masking tape.

  Next, the upper surface portion of the inner box 2 and the main body are heat-welded to form the inner box 2. Next, the vacuum heat insulating material 4 is bonded to the surface of the inner box 2 with an epoxy resin. At this time, since heat insulation such as hot water or a cold insulation material such as ice water enters the space connected by the opening 10 of the inner box 2, the inner box 2 is regarded as a heat source, and the orientation of the fibrous core material 12 is Affix it so that it is almost perpendicular to the heat transfer direction from the heat source.

  Next, the inner box 2 with the vacuum heat insulating material 4 attached is installed in the main body of the outer box 3, and at the same time, the moisture adsorbing material 7 and the gas adsorbing material 8 are also installed in the gap portion. Calcium oxide was used for the moisture adsorbing material 7 and Cu-substituted ZSM-5 type zeolite was used for the gas adsorbing material 8. The moisture adsorbing material 7 is put in a non-woven fabric, the gas adsorbing material 8 is sealed, and the device is structured to be softened by heating and opened.

  And the upper surface part of the outer case 3 is match | combined and heat welding is carried out. The welded portion is the outer periphery and the peripheral portion of the exhaust port 9 and the opening 10. At this time, a non-woven fabric is stuck on one of the exhaust ports 9 so that the powder core material 5 does not come off when the powder core material 5 is sealed.

  And the powder core material 5 is press-fitted with air from the exhaust port 9 where the nonwoven fabric is not pasted. At this time, the pressure is reduced by a vacuum pump from the exhaust port 9 on which the nonwoven fabric is pasted so that the powder core material 5 is easily sealed. As the powder core material 5, a mixture of 95 wt% dry silica having an average primary particle size of 100 nm or less and 5 wt% carbon black is used.

The powder core is press-fitted with a piston at a pressure of 0.5 kg / cm ² . The vacuum heat insulating material 4 does not occupy the entire space 6, and so-called corner portions are cavities, so that they are press-fitted through the cavities. The powder core material is sealed so as to have a density of 130 kg / m ³ .

  After filling the core material, the space 6 is decompressed from the exhaust port 9 and decompressed to 13 Pa or less, and the exhaust port 9 is pinched and sealed while being decompressed, whereby the vacuum heat insulation box 1 is completed. After completion, by heating the vacuum heat insulation box 1 at 100 ° C., the gas adsorbing material 8 is opened, gas adsorbing ability is expressed, and reliability is maintained.

Next, the manufacturing method of the vacuum heat insulating material 4 is demonstrated. Glass fiber is used for the fibrous core material 12, and a glass fiber assembly having an average fiber diameter of 3.5 μm is heated in a pressurized state to maintain a density of about 200 kg / m ^3. Is used. The average fiber diameter is evaluated by an average value obtained by measuring N = 50 with a microscope, but is preferably in the range of 1 μm to 20 μm, and 2 μm to 10 μm has rigidity as a core material, and productivity and heat More preferable in terms of conductivity.

  Then, after drying the fibrous core material 12 in a drying furnace at 140 ° C. for 30 minutes, the three sides of the laminate film are sealed with the heat-welding layer 13 by heat-welding and formed into a bag shape, and moisture is adsorbed on the jacket material 11. Calcium oxide sealed in a nonwoven fabric as material 7 and ZSM-5 type zeolite substituted with Cu in a vacuum seal in a laminate film as gas adsorbent 8 are inserted, and the inside of the jacket material 11 is 10 Pa in a vacuum chamber. The opening is hermetically sealed by reducing the pressure so as to become the following, and heat-welding the heat-welding layer 13.

  At this time, when hermetically sealed, the vacuum heat insulating material 4 is compressed to the atmosphere, and using this atmospheric compression force, the laminate film containing the gas adsorbent 8 is pierced with a needle-like material and opened. The gas adsorbing ability is developed after hermetic sealing.

  At this time, the covering material 11 is a polyethylene terephthalate film (12 μm) as a surface protective layer, an aluminum foil (6 μm) having poor gas permeability as an intermediate layer, and a linear low density polyethylene film (50 μm) as a heat welding layer 13. ). After sealing, the density of the fibrous core material 12 slightly increases due to atmospheric compression.

Density of the fibrous core material 12 made of glass fibers after sealing in terms of thermal insulation performance and handling properties is more preferably in the range of 210~280kg / ^{m 3,} was made as a 240 kg / ^{m 3.} Here, the core material is formed without using the binder, but the core material may be formed at a lower temperature using the binder.

  If the surface property does not matter, the glass fiber aggregate may be hermetically sealed as it is. In that case, since the number of manufacturing steps is reduced, productivity is improved.

  The thermal conductivity of the vacuum heat insulating material 4 thus formed was measured with an auto lambda manufactured by Eihiro Seiki. As a result, the thermal conductivity was 0.0011 to 0.0017 W / mK at an average temperature of 24 ° C., and had a heat insulation performance 10 times or more that of a general-purpose hard urethane foam.

  When hot water of 95 ° C. is poured from the opening 10 of the vacuum heat insulating box 1 produced as described above, the opening 10 is closed and left for 24 hours, the hot water temperature is 75 ° C. and has good heat retention characteristics. Moreover, even if the same evaluation was repeated 30 times, no difference was observed in the heat retention characteristics.

  Next, a mechanism for increasing the internal pressure of the vacuum heat insulating box 1 will be described.

  Air or water vapor from outside air enters the vacuum heat insulating box 1 through the material of the outer box 2 or the inner box 3 or the welding / welding location. Then, air or water vapor that has entered the space 6 enters the vacuum heat insulating material 4 through the heat welding layer 13.

  Here, factors affecting the amount of air and water vapor intrusion affect the pressure difference between the outside and inside, the length and area of the heat-welded layer connecting the outside and inside, the type of gas, temperature, humidity, etc. If the manufacturing process is the same, the influence by the pressure difference between the outside and the inside is great.

  Therefore, the pressure difference between the space 6 of the vacuum heat insulation box 1 and the outside air is 1 atm. Depending on the gas permeability of the outer box 2 and the inner box 3, air components enter the space 6. The amount is very small, and varies depending on conditions such as space volume, gas permeability, temperature, etc., but the internal pressure rises about several tens Pa even after one year, and the pressure around the vacuum heat insulating material 4 is low. Thereby, the air component which penetrates into the vacuum heat insulating material 4 through the heat welding layer 13 is further minute, and the heat insulating performance of the vacuum heat insulating material 4 hardly deteriorates and has long-term reliability.

  Moreover, the heat insulation performance of the vacuum heat insulating material 4 hardly deteriorates as described above due to the influence on the heat insulation performance of the vacuum heat insulation box 1 due to the internal pressure increase in the space 6. The powder core material 5 is used in places other than the vacuum heat insulating material 4. If the powder core material 5 has the same degree of vacuum as the fiber core material 12, the heat insulation performance is inferior, but the air gap distance is small and the decrease in heat insulation performance with respect to the pressure rise is small. Therefore, although depending on the core material, even if the pressure is increased by several hundred to 1,000 Pa, the heat insulation performance is not lowered and high reliability is obtained. Therefore, it is possible to form the vacuum heat insulation box 1 having both the high heat insulation performance of the fibrous core material 12 and the high reliability of the powder core material 5.

  The ratio of the vacuum heat insulating material 4 and the powder core material 5 in the vacuum heat insulating box 1 is not particularly limited, but if the ratio of the vacuum heat insulating material 4 is large and the ratio of the powder core material 5 is small, the heat insulating performance is improved. However, long-term reliability decreases. On the contrary, if the proportion of the vacuum heat insulating material 4 is small and the proportion of the powder core material 5 is large, the heat insulating performance is lowered, but the long-term reliability is improved.

  The required performance and long-term reliability differ depending on the application and usage conditions, the size of the vacuum heat insulating material, etc., so the optimum specifications cannot be generally limited, but the characteristics of the vacuum heat insulating material 4 and the powder core material 5 are different. In order to save, it is desirable to use in the range of 1: 9 to 9: 1.

  Moreover, the vacuum heat insulation box 1 normally depressurizes the space 6 from the exhaust port 9 so that the outer box 2 and the inner box 3 are compressed by the atmospheric pressure. If the outer box 2 and the inner box 3 do not have enough strength to withstand atmospheric pressure, or if the space 6 does not have a core material having compressive strength that can withstand atmospheric pressure, the outer box 2 or inner box 3 is deformed. Although it depends on the degree of deformation, there is a risk that the heat insulation performance may be reduced due to a decrease in the thickness of the heat insulation layer, cracks or the like may occur, and outside air may enter the space 6.

  However, the vacuum heat insulating material 4 is compressed to the atmosphere from the beginning, and even if the space 6 is depressurized, the vacuum heat insulating material 4 is not deformed from the initial thickness, and the vacuum heat insulating material 4 is installed in the space 6 as a spacer. Also effective. When a metal or resin is used as a spacer, it causes heat leak, but the vacuum heat insulating material 4 has excellent heat insulating performance, and there is no problem of heat leak.

  Further, it is preferable that the vacuum heat insulating material 4 has the same thickness as the space 6 because the deformation is small and the heat insulating performance is excellent.

  In practice, the orientation direction of the fibrous core material 12 is completely perpendicular to the heat transfer direction of the vacuum heat insulation box 1 because the heat transfer direction is not uniform and the fibrous core material 12 is completely Therefore, the vertical direction may be within a range of 70 to 110 degrees with respect to the main heat transfer direction.

  Further, the powder core material 5 is excellent in pressure dependency because the air gap distance is short, and is superior to the fiber-based material in order to obtain long-term reliability. In addition, the solid thermal conductivity is low, and a silica-based material is excellent as a core material for a vacuum heat insulating material as a powder core material.

  Moreover, since the vacuum heat insulating material 4 is inserted into the space 6 of the vacuum heat insulating box 1 as a core material, the amount of the powder core material 5 enclosed is significantly smaller than that of the entire space, and the powder core material 5 Less time is required for encapsulation and decompression, and productivity can be improved.

  The type of the powder core material 5 is not particularly limited, but is filled with an inorganic powder such as silica, pearlite, and carbon black, an organic powder such as a synthetic resin powder, or a mixture of the powder as it is, or air permeability. There are methods such as filling a certain bag and using it, or solidifying with a fiber binder or an inorganic or organic liquid binder.

  In particular, since the average primary particle size is 100 nm or less, the particle size is excellent in that the decrease in the heat insulation performance against the internal pressure is small, and such silica powder corresponds to dry silica produced by a dry method, and is most preferable. .

  Further, it is desirable that the moisture adsorbing material 7 is provided with the ability to suppress an increase in internal pressure by removing moisture adsorbed on each constituent material and further by adsorbing water vapor entering from outside air.

  Also, the installation location is preferable because it is most effective by being placed in contact with each of the vacuum heat insulating material 4 and the powder core material 5, and either the fibrous core material 12 or the powder core material 5 is preferable. But it is effective.

  If the moisture adsorbing material 7 is installed only on the fibrous core material 12, even if water vapor enters the space 6 for some reason, such as the outer box 2 or the inner box 3 being damaged, the heat insulating layer 13 is used for vacuum insulation. Since the water vapor entering the material 4 is adsorbed, the heat insulating performance of the vacuum heat insulating material 4 can be maintained, and the reliability can be maintained. Further, if the moisture adsorbing material 7 is disposed so as to be in contact with only the powder core material 5, it is possible to suppress an increase in internal pressure in the space 6 by adsorbing water vapor entering the space 6 and maintain reliability.

  Further, although the type of the moisture adsorbent 7 is not particularly limited, specifically, as the physical adsorbent, synthetic zeolite, activated carbon, activated alumina, silica gel, dosonite, hydrotalcite, metal complex, etc. are desirable, As chemical adsorbents, oxides of alkali metals and alkaline earth metals, hydroxides of alkali metals and alkaline earth metals, etc. can be used, especially lithium oxide, lithium hydroxide, calcium oxide, calcium hydroxide, Magnesium oxide, magnesium hydroxide, barium oxide, and barium hydroxide are effective. Calcium chloride and phosphorus pentoxide are also effective.

  Moreover, the gas adsorbent 8 can suppress an increase in internal pressure by adsorbing an air component remaining without being fully decompressed or an air component entering from the outside air, thereby improving long-term reliability. .

  Further, the gas adsorbent 8 is preferably installed in contact with each of the vacuum heat insulating material 4 and the powder core material 5 because it is most effective, and the fibrous core material 12 and the powder core material are preferable. Either one of 5 will be effective. If the gas adsorbent 8 is installed only on the fibrous core 12, even if an air component enters the space 6 for some reason, such as the outer box 2 or the inner box 3 being damaged, a vacuum is passed through the heat-welded layer 13. Since the air component which penetrates into the heat insulating material 4 is adsorbed, the heat insulating performance of the vacuum heat insulating material 4 can be maintained, and the reliability can be maintained. Further, when the gas adsorbent 8 is installed so as to be in contact with only the powder core material 5, an increase in internal pressure in the space 6 can be suppressed by adsorbing air components that enter the space 6, and reliability can be maintained. .

  Further, as the gas adsorbent 8, the adsorption mechanism may be any of physical adsorption, chemical adsorption, occlusion, and sorption, but a substance that acts as a non-evaporable getter is good.

  Specifically, it is a physical adsorbent such as synthetic zeolite, activated carbon, activated alumina, silica gel, dosonite, hydrotalcite.

  As the chemical adsorbent, oxides of alkali metals and alkaline earth metals, hydroxides of alkali metals and alkaline earth metals, etc. can be used. In particular, lithium oxide, lithium hydroxide, calcium oxide, calcium hydroxide, Magnesium oxide, magnesium hydroxide, barium oxide, and barium hydroxide are effective.

  In addition, calcium sulfate, magnesium sulfate, sodium sulfate, sodium carbonate, potassium carbonate, calcium chloride, lithium carbonate, unsaturated fatty acid, iron compound and the like also act effectively.

  In addition, an alkaline compound such as sodium hydroxide or potassium hydroxide is preferable for adsorbing carbon dioxide.

  In addition, it is more effective to apply a getter material obtained by singly or alloying materials such as barium, magnesium, calcium, strontium, titanium, zirconium, vanadium, and lithium.

  Furthermore, in order to adsorb and remove at least nitrogen, oxygen, moisture, and carbon dioxide, the getter material can be applied in various mixtures.

  However, ZSM-5 type zeolite with exchanged copper ions has a higher gas adsorption amount per unit weight at room temperature than other zeolites and metal adsorbents, and adsorbs a large amount of air with a small amount of gas adsorbents. Even a low vacuum of about 10 Pa, which exhibits heat insulation performance as a vacuum heat insulating material, exhibits its adsorption ability, and also adsorbs nitrogen that is difficult to adsorb with nonpolar molecules having a large binding energy of about 940 kJ / mol. The gas adsorbent 8 is the most preferable because it is possible, has high performance and is effective, and can save space.

  In addition, the gas adsorbing material 8 includes not only air components but also water vapor adsorbing materials. Preferably, the gas adsorbing material 8 is encased in the water adsorbing material 7 or the water adsorbing material 7 is used to adsorb the gas. It is more preferable that an air component and water vapor reach the material 8 because the adsorption capacity of the gas adsorbing material 8 can be maintained for a long time.

  As the covering material 11, an AL foil laminated film and an AL vapor-deposited laminated film are preferable because they have excellent gas permeability, and even if a metal foil other than AL is used, the effect does not change. Further, a film material on which an inorganic material such as silica, diamond-like carbon, or alumina is deposited and coated may be used.

  Moreover, although the gas permeability is inferior to that of metal foil or inorganic material coating, it may be a gas permeability resin such as ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon, polyvinyl alcohol, More preferably, an inorganic material such as silica, diamond-like carbon, or alumina is vapor deposited and coated to improve gas permeability.

  Further, a metal material such as stainless steel may be used for the jacket material and welded.

  Moreover, when polyethylene is used for the heat welding layer 13, since polyethylene can be welded at a relatively low temperature, welding by additional heating is easy, and the vacuum heat insulating material 4 can be provided at a lower cost.

  Further, a protective layer made of polyethylene terephthalate may be provided on the outermost layer of the jacket material 11. By disposing a material for the purpose of surface protection in the outermost layer of the jacket material 11 in this way, it has a function of suppressing the occurrence of pinholes by exhibiting more reliable scratch resistance and puncture resistance. And the vacuum heat insulating material 4 which has long-term reliability can be provided, and also the vacuum heat insulation box 1 which has long-term reliability can be provided. Also. Polyethylene terephthalate is an inexpensive material and can provide the vacuum heat insulating material 4 at a lower cost.

  As the fibrous core material 12, short glass fibers are suitable as a general-purpose industrial material. More preferably, the fiber assembly is composed of a laminate of short glass fiber webs, and the webs are joined by a minimum amount of fiber entanglement capable of maintaining the integrity of the laminate, and are uniformly laminated in the thickness direction. Is preferred.

  The fiber diameter is not particularly specified, but finer fiber diameter can provide better heat insulation performance. However, from the viewpoint of economy, it is desirable to use one having an average fiber diameter of 3 to 5 μm.

  Moreover, as a gas poorly permeable material which comprises the outer box 2 and the inner box 3, metal materials, such as stainless steel and iron, and glass material are preferable. Since a glass material is easily broken, a metal material is more preferable.

  In addition, when using a resin material whose solid thermal conductivity is smaller than that of metal and can improve heat insulation performance, and which has a small specific gravity and can be reduced in weight, an ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon It is preferable to use a gas permeable resin such as polyvinyl alcohol, crystalline polyethylene terephthalate, or crystalline syndiotactic polystyrene.

  Furthermore, in order to improve the low gas permeability, vapor deposition / coating of resin with insert molding of AL foil laminate film and AL vapor deposition laminate film, and inorganic materials such as silica, diamond-like carbon and alumina on the surface Is more preferable in order to improve reliability.

(Embodiment 2)
FIG. 3 is a cross-sectional view of the vacuum heat insulating material installed in the space of the vacuum heat insulating box according to Embodiment 2 of the present invention. In addition, the thing of the same name and effect | action as Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits description.

  In FIG. 3, the vacuum heat insulating material 4 has a heat-sealing layer 14 on the surface on which the outer jacket material 11 is located, and the thermal welding layers 14 of the outer jacket material 11 facing each other along the fibrous core material 12. The upper and lower heat welding layers 14 are integrated by heat welding up to the fibrous core material 12. In addition, the thickness of the heat welding layer 14 is kept constant.

  Next, a manufacturing method for performing heat welding along the fibrous core material 12 will be described. When the vacuum heat insulating material 4 produced in the same manner as in the first embodiment is left in a constant temperature furnace at 130 ° C., which is higher than the temperature at which the heat welding layer 14 is welded, for about 10 minutes, the entire vacuum heat insulating material 4 is pressurized by atmospheric compression. Therefore, the entire vacuum heat insulating material 4 is heat-welded and heat-welded up to the fibrous core material 12.

  Since the heat-welded layer 14 is welded up to the fibrous core material 12, the range of the heat-welded layer 12 can be widened to improve the sealing performance, and the outer peripheral edge can be cut to the nearest. The bulkiness is reduced, the powder core material 5 is easily filled, and the outer peripheral end portion is reduced, so that the area ratio occupied by the high-performance vacuum heat insulating material 4 in the space 6 can be increased, thereby improving the performance. Can be achieved.

  In addition, since the vacuum heat insulating material 4 is included in the space 6, the outer peripheral edge is cut out to the near end, the width of the heat-welded layer 14 becomes narrow, and air components easily enter the inside of the vacuum heat insulating material 4. Even if it becomes conditions, since the space 6 is a decompression space, it has sufficient reliability.

(Embodiment 3)
FIG. 4 is a longitudinal sectional view of the vacuum heat insulation box according to the third embodiment of the present invention. In addition, description of the same name and action as in the first and second embodiments is omitted.

  Next, the manufacturing method of the solidified powder core material 15 and the vacuum heat insulating material 4 is demonstrated.

The solidified powder core 15 has an average fiber diameter of 10 μm corresponding to 10 wt% of the powder obtained by mixing and stirring 95 wt% of dry silica having an average primary particle diameter of 100 nm or less and 5 wt% of carbon black. The following glass fibers are mixed and further stirred, and molded by pressing 1 MPa so that the core material density becomes 130 kg / m ³ .

  For forming, the vacuum heat insulating material 4 and the powder core material 5 are placed in a predetermined mold, and simultaneously pressure-molded and integrated. The solidified powder core 15 is placed in the space 6, the inside of the space 6 is decompressed and sealed from the exhaust port 9, and the vacuum heat insulating box 1 is manufactured.

  Since the powder core material 5 is much powdered, easily scattered, and has a small density, it is difficult to handle, takes a lot of man-hours for filling, and has a lot of loss. Therefore, it is desirable to encapsulate the solidified powder core material 15 because it is advantageous in terms of process, safety, and productivity.

  Dry silica having an average primary particle size of 100 nm or less is solidified by mixing and pressing with short glass fibers. Even with the same composition, it is not solidified by wet silica produced by a wet method.

  This may be due to the fact that powders with small particle diameters cause intermolecular forces to act and the powders adhere to each other, or because they are dry, the surface functional groups are few and the mutual repulsion is so small that the powders are likely to adhere to each other. Therefore, in order to produce the powder core material 15 solidified by a molding method such as pressurization, it is necessary to use dry silica having an average primary particle diameter of 100 nm or less.

  The fiber material is necessary for maintaining the strength of the agglomerated dry silica. The fiber material is necessary because it aggregates without the fiber material, but becomes very brittle.

  Further, it is considered that the glass fiber has an average fiber diameter of 10 μm or less, so that the specific surface area increases because the fiber diameter of the glass fiber is small, that is, the surface energy increases, and the affinity with the powder core material 5 increases. Therefore, when the powder core material 15 solidified by a molding method such as pressurization is produced, a stronger molded body can be produced by using glass fibers having an average fiber diameter of 10 μm or less.

  In addition, a strong molded body can be obtained by the above combination, and a molded body having flexibility can be obtained because it has elasticity. This is because the glass fiber has an average fiber diameter of 10 μm or less, so that the bending elasticity is improved and the glass fiber can have flexibility.

  Further, the glass fiber addition amount is 0.5 to 40 wt% because if the addition amount is too small, the shape of the molded body cannot be maintained, and if it is too large, the heat insulation performance becomes dependent on the fiber and the heat insulation performance is deteriorated. Because.

  Further, when 1 to 30 wt% of carbon black is mixed with dry silica, the heat insulation performance is further improved. Thereby, heat insulation performance improves rather than the vacuum heat insulating material using the conventional silica powder molded object.

  For example, carbon black and titanium oxide are known to work as radiation inhibitors at high temperatures as powders added to silica to improve thermal insulation performance. It is done. Although this reason is not certain, it is considered that solid heat conduction is reduced by some action of silica powder and carbon black.

  The addition amount of the powdery carbon material is preferably 1 to 30 wt%. This is because if the addition amount is too small, there is no effect of improving the heat insulation performance, and if it is too large, the heat insulation performance becomes dependent on the powdered carbon material and the heat insulation performance deteriorates, or gas generation increases under reduced pressure. This is because the heat insulation performance deteriorates.

In addition, the density of the solidified powder core material 15 can be adjusted by pressure molding. If the density of the solidified powder core 15 is too small, the shape as a molded body cannot be maintained, and it is easy to collapse at the time of dismantling, and part of the powder is scattered, so that the density is 100 kg / m ³ or more. From the viewpoint of decreasing the porosity, increasing the solid thermal conductivity, and reducing the heat insulation performance, 300 kg / m ³ or less is preferable.

Moreover, since it is necessary to perform pressure molding in order to mold the solidified powder core material 15, the core material is sealed and then pressure molded. In order for the sealed pressure to remain constant even if it is held in the hand after dismantling, a pressure of 0.5 N / mm ² or more is desirable.

  The vacuum heat insulation box concerning this invention can maintain heat insulation performance over a long period of time. For this reason, if it uses it for cold storage apparatuses, such as a refrigerator, and thermal insulation apparatuses, such as an electric water heater, a rice cooker, a thermal insulation cooker, and a hot water heater, it will show the energy-saving effect excellent over the long term. Also, it can be applied to uses such as container boxes and cooler boxes that require cold storage.

  Also, it can be applied to any heat insulation applications such as thermal equipment such as heat pump thermal insulation tanks and physical objects to be protected from heat and cold by using the same technology to improve the efficiency of heat storage warming devices for automobiles.

Sectional drawing of the vacuum heat insulation box in Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material installed in the space of the vacuum heat insulation box in Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material installed in the space of the vacuum heat insulation box in Embodiment 2 of this invention The longitudinal cross-sectional view of the vacuum heat insulation box in Embodiment 3 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulation box 2 Outer box 3 Inner box 4 Vacuum heat insulating material 5 Powder core material 6 Space 8 Gas adsorbent material 11 Cover material 12 Fibrous core material 13 Thermal welding layer 14 Thermal welding layer 15 Solidified powder core material

Claims (9)

A vacuum heat insulating material and a powder core material, each of which is formed by vacuum-sealing a fibrous core material with a jacket material made of a gas permeable material, in a space constituted by an outer box and an inner box each made of a gas permeable material. A vacuum heat insulating box having a vacuum double wall structure in which the space is sealed under reduced pressure. The outer cover material has a heat-sealing layer on the inner surface, and the heat-welding layers of the outer cover materials facing each other are heat-welded to the fibrous core material along the fibrous core material. The vacuum heat insulation box according to claim 1, wherein The vacuum heat insulating material is oriented so that the fibrous core material of the vacuum heat insulating material has orientation, and the orientation direction of the fibrous core material is substantially perpendicular to the heat transfer direction of the vacuum heat insulating box. It arrange | positions, The vacuum heat insulation box of Claim 1 or 2 characterized by the above-mentioned. The vacuum heat insulating box according to any one of claims 1 to 3, wherein the powder core material is dry silica having an average primary particle diameter of 100 nm or less. The powder core material is pressure-molded by mixing a glass fiber material having an average fiber diameter of 10 μm or less with the dry silica so that the content in the powder core material is 0.5 to 40 wt%. The vacuum heat insulating box according to claim 4. The vacuum heat insulating box according to claim 4 or 5, wherein 1 to 30 wt% of carbon black is mixed with the dry silica. The vacuum heat insulating box according to any one of claims 1 to 6, further comprising a gas adsorbing material for adsorbing a gas in the vacuum heat insulating material in the vacuum heat insulating material. The vacuum heat insulating box according to claim 1, further comprising a gas adsorbent for adsorbing the gas in the space in the space. The vacuum heat insulating box according to claim 7 or 8, wherein the gas adsorbent is ZSM-5 type zeolite subjected to copper ion exchange.